I use an all fleet oil ..I have for years.. Now its Delo 15-40 in every thing I own.. I change my motorcycles at 2000 miles.. in normal use.. I sold an 82 Yamaha Venture that I put 280,000 miles on and had no problems..It now has over 300,000 miles on it and still has no problems.. The Goldwing 1500 w/Champion escort sidecar that replaced the Venture only has 50,000 miles on it.. The 1500 Vulcan Classic FI that replaced the 82 Honda 650 Night Hawk with 180,000 only has 10,000 on it.. We put over 450,000 miles on our 240 Diesel.. 400,000 thousand on our 250S. and some where near 300,000 on our 300CD.. On all them you could still see the paint on the valve springs when you adjusted them.. The engines were clean inside.. used very little oil..

Last week I helped a friend adjust the valves on his 77 300D.. I had done it before and the engine was clean inside.. He has switched to a Syn oil.. and now says he changes every 8000 miles.. The engine was not clean inside.. Had like a layer of sludge on the springs and inside the engine.. He said it has been that way the last two valve adjustments.. It seems to run OK.. I did mic. a few of the cam lobes and could see no wear.. I have to wonder how much he is going to save by not changing oil and filter over just doing at the 3000 mile mark and using a dino oil.. For the difference in price between the dino oil and the syn oil you can change the dino oil every 3 thousand and to break even you have to change the syn oil every 10000.. Cost of 3 oil changes with filter with dyno oil is.. 63 bucks.. Cost of one syn oil change with filter is 71 bucks at the prices we pay at the local Shucks for oil.. Filters at 7 bucks each .. And the savings is??????

I think I will stick with what I know works.. There is no question that the Syn oils are better oils... But these old engines were not well vented.. and did not run as clean as the newer engines.. I wonder if that will not bite us in time..

Ken